利用分子标记定位玉米小粒突变体mn7基因的研究

利用甲基磺酸乙酯(EMS)对玉米自交系郑 58进行诱变，获得 1个可以稳定遗传的小粒突变体mn7(miniature 7)。mn7成熟子粒表现为体积变小、子粒偏白、胚乳发育缓慢，百粒重降低 60.2%，粒长、粒宽、粒厚均极显著降低。mn7突变体的子粒在授粉后 15 d即可观察到明显小于野生型的子粒。对其自交后代和回交后代的遗传分析表明，该性状受隐性单基因控制。用mn7纯合体与自选玉米自交系 19HL3012杂交构建的包含 348个个体的 F₂分离群体，将该基因定位于玉米第 7染色体上 bin7.02区域内分子标记 umc2327和 SYM232之间 5.8 cM的范围内，距umc2327为 4.4 cM，距 SYM232为 1.4 cM。初步的生物信息学分析表明， mn7可能是 1个新基因或新等位基因。

Mapping of Miniature Kernel Mutant mn7 Gene Using Molecular Marker in Maize

A stable miniature kernel mutant, named mn7(miniature 7), was generated by ethylmethane sulfonate (EMS) mutagenesis with an inbred line Zheng 58 in maize. Compared with wild type, mature kernels of mutant mn7 showed smaller volume, whiter, slow endosperm development, 100-kernel weight decreased by 60.2%, and kernel length, width and thickness were all significantly reduced. The kernel of the mn7 mutant were significantly smaller than that of the wild type at 15 days after pollination(DAP). Genetic analysis of its inbred progeny and backcross progeny showed that the mutant trait is controlled by a single recessive gene. An F₂ segregation population consisting of 348 individuals derived from 19HL3012×mn7 was used as the mapping population and the mn7 gene was located in a region of 5.8 centi-Morgan(cM) flanked by the molecular markers umc2327 and SYM232 in the bin 7.02 on chromosome 7. The genetic distance from mn7 to umc2327 was 4.4cM and it was 1.4cM from mn7 to SYM232. Bioinformatics analysis indicated that mn7 might be a new gene or allele.